"Where it gets interesting is in trying to answer the question of what is enough? Sure, more bits are more accurate, but can the human ear tell the difference. In most cases, once you go beyond true 16-bits, the answer is no. All benefits above 16-bits/48 kHz are very small refinements, not monumental improvements. What really is going on, is that the advertised "16-bit/48 kHz" recordings of yesterday weren't. They used 16-bit converters but their accuracy was not 16-bits, it was more like 14-bits. Similarly today, the advertised "24-bit" converters are not 24-bit accurate, but they are certainly at least 18-bit accurate, and that makes an audible difference. So, if you can find a true 16-bit system and compare it with a typical 24-bit system of today, they will sound very nearly identical.
And the sampling rate getting faster makes even less of an audible difference. For example if you compare a typical 16-bit/96 kHz system against a 24-bit/48 kHz, you will pick the 24-bit system every time. If you have a choice, always choose more bits, over a higher sampling rate."
- Rane Pro Reference,
http://www.rane.com/par-d.html
A while ago I did look at a review for the Audigy THX sound card and in the performance measurements there were differences between various D/A converter modes, i.e. 16 bit versus 24 bit signal-to-noise ratio, 96 kHz dynamic range versus 44.1 kHz etc. It is likely that the D/A converter in your Yamaha will perform differently in the same way and it could have better technical performance at 96 kHz than at 48 kHz. This is perhaps why some digital receivers and DVD/CD players have upsampling. I think that the technical difference will probably not result in much, if any, audible difference. 90 dB signal-to-noise ratio and 90 dB crosstalk separation at 1 kHz isn't going to sound different to 80 dB s/n, 80 dB crosstalk.
D/A's will probably have excellent s/n's for greater than 16 bit, like for Dolby Digital and DTS, where such an improvement is worthwhile.
